A magnitude 5.5 earthquake struck Tokyo, Chiba and Kanagawa prefectures at around 9:11 a.m. on Monday, registering an intensity of 4 on the Japanese scale of 0 to 7 in the hardest hit areas. There is no risk of tsunami.
Police and fire departments in Tokyo and surrounding areas say there have been no reports of injuries or damage caused by the quake.
The Japan Atomic Power Company says the Tokai Daini nuclear power plant at the village of Tokai in Ibaraki Prefecture is currently suspended and no abnormalities have been reported.
The company says a tremor with an intensity of one hit the village. It says monitoring posts around the plant showed no change in radiation levels as of 9:20 a.m.
Aviation authorities in Tokyo say flights at Haneda and Narita international airports have so far been unaffected by the quake.
Central Japan Railway Company says it temporarily suspended its Shinkansen bullet train service between Tokyo and Odawara, but that it has since resumed.
Tohoku, Joetsu, Hokuriku, Akita and Yamagata bullet trains are in normal operation.